Many engineers continue to seek high-strength and lightweight parts for various industrial applications such as, but not limited to, construction, building, and aerospace/automotive applications. Lightweight components may be desirable, for example, in some applications to provide favorable reductions in shipping costs or installation and repair costs. In addition, higher-strength components may exhibit enhanced performance characteristics such as stiffness, improved load capability, improved environmental durability, erosion resistance, and impact resistance. Polymeric materials may be attractive materials for component fabrication in a number of industries because they are lightweight and moldable into a range of complex shapes by conventional processes. However, parts formed from polymeric materials may be limited to relatively few structurally loaded applications as they are less structurally capable than metallic components of similar geometry. In contrast, parts formed from metallic materials are strong and less prone to structural failure compared to similarly-dimensioned polymeric parts, but they may be too heavy for some weight-sensitive applications. Consequently, there is a need for parts having both lightweight and high-strength properties for a range of applications.
IsoTruss® structures are ultra-lightweight and high-strength composite structures of resin and continuous fibers with potential for use in numerous applications such as bicycle frames, freeway pillars, telephone poles, and aircraft construction. IsoTruss® structures are cage-like lattice structures which consist of a plurality of aligned and straight axial posts connected by a series of pyramidal structures extending in the lateral direction. When viewed in cross-section, the IsoTruss® structure has a symmetrical star-shape with the axial posts intersecting with triangles at “nodes”. It may take on various configurations which may vary in the number of posts, interconnecting pyramids, and nodes. Current manufacturing methods for IsoTruss® structures involve winding selected continuous fibers over a metallic mandrel and then carefully removing the metallic mandrel. Remarkably, the IsoTruss® structure exhibits the highest, or at least one of the highest, specific strengths (i.e., strength per unit weight) along its axial direction of currently known materials and structures surpassing steel at only a fraction (about 9%) of the weight. Although remarkable at absorbing loads in the axial direction, the Isotruss® structure may be weaker in the lateral direction. To extend the use of IsoTruss® for applications where high-strength in the lateral direction is necessary, systems are needed to improve the lateral strength of such structures.